:root {
    --primary-color: #2c3e50;
    --primary-light: #34495e;
    --secondary-color: #3498db;
    --accent-color: #1abc9c;
    --success-color: #2ecc71;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
    --light-bg: #f8f9fa;
    --dark-text: #2c3e50;
    --medium-text: #7f8c8d;
    --light-text: #95a5a6;
    --border-color: #e1e8ed;
    --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    --hover-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e7f1 100%);
    color: var(--dark-text);
    line-height: 1.6;
    min-height: 100vh;
    margin: 0;
    padding: 15px;
}

.register-wrapper {
    display: flex;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    overflow: hidden;
    width: 100%;
    max-width: 950px;
    margin: 20px auto;
    transition: var(--transition);
}

.register-wrapper:hover {
    box-shadow: var(--hover-shadow);
}

.left-panel {
    flex: 1;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-light) 100%);
    color: white;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

.left-panel h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.left-panel p {
    font-size: 1rem;
    opacity: 0.9;
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.right-panel {
    flex: 1;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.right-panel h2 {
    color: var(--dark-text);
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-align: center;
    font-size: 1.8rem;
}

.input-group {
    margin-bottom: 1.3rem;
}

.input-group label {
    font-weight: 500;
    margin-bottom: 0.5rem;
    display: block;
    color: var(--dark-text);
    font-size: 0.95rem;
}

.form-control {
    border-radius: var(--border-radius);
    padding: 0.9rem 1.1rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    font-size: 1rem;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.05);
}

.form-control:focus {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.25);
}

.input-group-text {
    background-color: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius) 0 0 var(--border-radius);
    color: var(--light-text);
    padding: 0.9rem 1.1rem;
}

.gender-group {
    display: flex;
    gap: 15px;
}

.gender-group label {
    font-weight: normal;
    margin-bottom: 0;
    display: flex;
    align-items: center;
    cursor: pointer;
    color: var(--medium-text);
}

.gender-group input {
    margin-right: 6px;
    width: 16px;
    height: 16px;
}

.file-upload-container {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background-color: var(--light-bg);
}

.file-upload-container:hover {
    border-color: var(--secondary-color);
    background-color: #eef5fb;
}

.file-upload-container input[type="file"] {
    display: none;
}

.upload-text {
    color: var(--medium-text);
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

#avatarPreview {
    margin-top: 15px;
    text-align: center;
}

#previewImage {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--primary-color);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.btn-login {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    border-radius: var(--border-radius);
    padding: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
    width: 100%;
    margin-top: 1.2rem;
    font-size: 1rem;
    color: white;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

.btn-login:hover {
    background-color: var(--primary-light);
    border-color: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: var(--hover-shadow);
}

.footer {
    text-align: center;
    margin-top: 2rem;
    color: var(--light-text);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .register-wrapper {
        flex-direction: column;
    }

    .left-panel {
        padding: 2rem;
    }

    .right-panel {
        padding: 2rem;
    }
    
    .gender-group {
        gap: 12px;
    }
}